I currently have an AR with no white light and a DBAL on top. I'm also looking to eventually pick up a DBAL I2 for my other carbine. Ideally, I'd like to mount a flash light at 10 o'clock, and use a button cap instead of a tape switch to activate it. Preferably I'd like to upgrade both carbines with pretty much the same light option, in anticipation of picking up another IR laser.

I've been looking at the Surefire Scout and the Streamlight Rail mount lights. I'm wondering if anyone has successfully mounted one of these lights at 10 to 11 o'clock with a bulky IR laser at 12 o'clock. If so, I'd love to know what combo worked out.

Surefire Scout with an Arisaka or similar might work.

What rail?

If you havent seen this: Official Weapon Mounted IR Laser Pic Thread
Heres one of mine:

Dbal i2 - Larue LT271 mount
Unity Fusion Mlok - SF M300 (Running M600VB now)

That pic is what gave me the idea. 

I have a DD lite rail. I'm thinking of trying a thorntail mount. I used to have one for a G2X tactical light, and found it to hold the light very close to the rail. Just not sure if it will completely clear. 

Even with a thin profile rail a 10:00/11:00 light mount it's difficult to manipulate a push button tail cap with both hands. I haven't tried a dual activation switch like the SureFire SR07 D-IT yet, but I thinl it may be awkward to activate both at the same time with either hand. Your best option maybe either run a separate tape switch, one at 12 O'Clock, the second at 1 O'Clock position or buying a Steiner I2 9007 IR light/IR laser, D2, A3 or ATPIAL-C. IMHO it's paramount to be able to activate your IR laser and IR light at the same time consistently with either hand.

I just found my old clunky M951 Surefire in my bin of parts. After doing some reading today I decided I'll use this instead, and ordered an LED bulb replacement. This will work on my longer barreled carbine. I currently use an Insight tape switch at 12 o'clock that I really like for my laser. I was looking at the Surefire dual pressure pad that connects to both the laser and to a Surefire light. Does this setup work well? Is it worth the obscene price for the switch? Are there any other cheaper switch options out there?

Using that mount on the Geissele rail with a M600U, can it be scooted back to where the lens is even with the end of the rail?